1. Field of the Invention
The invention relates to a device for making-up or breaking-out joints of drill pipe, drill collars and the like in mouse hole pipe quickly and easily.
2. Description of the Prior Art
One of the existing powerless clamping device for drill pipe, drill collars and like in the mouse-hole pipe is of a turning plate type which is manually operated and the clamping is effected by turning an eccentric jaw plate. This type is suitable for making-up joints with a small torque, but if the making-up torque is large, the clamping device will be damaged. Another one is spiral guide downward clamping device which occupies a larger space and is complicated in structure. The two device mentioned above can only work in one rotational direction. This is the weakness of these kinds of clamping devices.